PDMS/CNF Nanocomposite Sensor Array for Pressure Sensing

Pressure sensing is a field that is rapidly advancing as driven by vast applications including biomedical devices, industrial automation, human-machine interfacing, and skin-like electronics. Recently significant amount of effort has been reported to develop new piezoresistive strain sensor made from polymers with carbon nanofillers. The widely used nanofillers with high electrical conductivity include carbon nanotubes, carbon nanofibers, and other carbon nanoparticles. However, most previous research focused on the improvement of material properties for sensing applications. Limited work balanced the sensor design and material innovation for real time pressure sensing. This paper presented a piezoresistance based pressure sensor array using flexible and stretchable polydimethylsiloxane (PDMS) polymer/carbon nanofiber (CNF) nanocomposite. In order to increase the sensitivity of the proposed sensor array, each sensing unit was optimized by selecting the appropriate shape and adjusting critical geometrical parameters using both finite element analysis and optimization algorithms. Considering different pressure range, two different set of sensing unit geometries were designed for the best performance in the pressure range of 50.100, and 150 psi maximum pressures. The developed sensor arrays were connected using a mesh grid approach. Preliminary sensor array experiments were tested to prove the concept. Finally, the developed pressure sensor arrays were characterized under both static and cyclic load conditions to demonstrate its sensor capability.